DOCSLIB.ORG

Acid Rain in Shenandoah National Park, Virginia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Acid Rain in Shenandoah National Park, Virginia Prepared in cooperation with the National Park Service Acid Rain in Shenandoah National Park, Virginia Visitors to Shenandoah National Park (SNP) enjoy the animal and plant The pH scale is a measure of how acidic (low pH) or alkaline life and the scenery but may not real- (high pH) a solution is. Rainwater is considered normal at 5.6 pH ize how vulnerable these features are to units. Shenandoah National Park rain typically is 10 times more various threats, such as invasion of exotic acidic than normal rain. plants and insects, improper use of park resources by humans, and air and water pollution. The National Park Service rain (currently about 4.6 pH units) falling mic, which means that each whole-num- strives to protect natural resources from onto an environment that has little inher- ber change indicates a 10-fold change in such threats to ensure that the resources ent ability to neutralize the acidic input acidity or alkalinity. For example, a pH of will be available for enjoyment now and and decades of exposure to acid rain have 4 is 10 times more acidic than a pH of 5. in the future. Because SNP has limited resulted in a fragile environment. When Rainwater is considered normal at 5.6 pH influence over the air pollution that the effects of acid rain are combined units; therefore, rain with a pH of 4.6, envelops the region, acidic deposition— with stressors, such as forest defoliation which typically occurs in SNP, is about commonly known as acid rain—is one of caused by the gypsy moth or conifer- 10 times more acidic than normal rain. the more challenging threats facing park ous tree demise caused by the hemlock Acid-neutralizing capacity (ANC)— managers. With the help of U.S. Geo- woolly adelgid, significant environmental the ability of a solution to neutralize logical Survey (USGS) scientists, park problems can develop, and park resources acidic inputs—is a quantitative measure managers can understand how acid rain become threatened. associated with pH (fig. 1). In general, interacts with ground- and surface-water water with a high ANC (for example, resources, which enables them to explain 500 units1) also has a high pH and is why reductions in air pollution can help good at neutralizing acidic inputs. In preserve park resources. Such under- Understanding pH and contrast, water with a low ANC (for standing also provides essential insight Acid-Neutralizing example, 25 units) has a low pH and is into ecosystem processes, as managers a poor neutralizer. Stream animals and strive to unravel and resolve other envi- Capacity plants (the biota) can be sensitive to and ronmental problems that are interrelated negatively affected by changes in ANC, to acid rain. The severity of acid rain and acidic particularly when it decreases to near Even though reductions in emissions streamwater is measured by the pH zero units, which can cause the biota to of acid-forming compounds mandated by scale—a quantitative measure of how suffer “acid shock.” Research on fish the Clean Air Act and Amendments have acidic (low pH) or alkaline (high pH) a indicates that many species are sensitive occurred since 1990, acid rain contin- solution is (fig. 1). A neutral solution, at ANC values less than 50 units. ues to fall in the eastern United States, which is neither acidic nor alkaline, has including SNP. The combination of acid a pH of 7 units. The pH scale is logarith- 1ANC concentration typically is expressed in microequivalents per liter. “Unit” is used here for simplifying purposes. Acid rain Fish begin Normal Baking Battery acid Vinegar to die rain soda Ammonia Lye 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Figure 1. Relations Acidic Alkaline of common solutions Neutral and acid-neutralizing capacity to the pH Low acid-neutralizing capacity Intermediate acid-neutralizing capacity High acid-neutralizing capacity scale. U.S. Department of the Interior Printed on recycled paper Fact Sheet 2007–3057 U.S. Geological Survey July 2007 Shenandoah National Park Streams Acid Rain Facts Shenandoah National Park streams start near the top of a mountain, usually as a spring or seep on a hillface. As the • Acid rain is caused by combustion of fossil fuels (gas, oil, coal) and to a much water flows downhill, the stream increases lesser extent by natural processes (volcanic emissions, forest fires). in size as more tributaries and ground • Combustion emits sulfur dioxide and nitrogen oxides (the two major contributors water contribute to the streamflow. Such to acid rain) into the atmosphere; these oxides can travel hundreds of miles from streams are called “headwater streams.” the source of emission. Because these streams begin with little water, contributions of acid rain can make • Sulfur dioxide and nitrogen oxides convert to sulfuric and nitric acids in the the streamwater more acidic. During atmosphere; the acids are deposited to the earth by wet deposition (rain, snow, storms, acid rain quickly reaches head- fog) and dry deposition (dry particles, gases), collectively referred to as “acidic water streams and can decrease the ANC deposition.” and pH of the stream temporarily. As the pulse of acidic water flows downstream, • Some of the largest emissions in the United States originate in the Ohio River the streamwater recovers to the pre-storm Valley and are carried downwind through the atmosphere toward Shenandoah ANC and pH values. National Park. Although the acidity of rain is spa- • The Clean Air Act, designed to reduce emissions, was passed in 1970, amended tially uniform across SNP, streamwater in 1990, and amended again in 1995. ANC and pH values vary substantially across the park. These differences are • In Shenandoah National Park, the annual average pH values of precipitation related to the underlying geology (bedrock for the following periods were: 4.53 for 1981–1990; 4.59 for 1991–1995; type) and topography (steepness of the 4.62 for 1996–2005. These pH values suggest incremental improvements in slope) of the watersheds. The three main response to the Clean Air Act amendments. bedrock types in SNP are basaltic, granitic, and siliciclastic. Basaltic rocks are the • Rain tends to be most acidic during the summer; longer periods between storms best of the three bedrock types at neutral- allow acids to build up in the atmosphere before being “rained out.” izing acidic inputs, siliciclastic rocks are • Individual pH values of rain well below 4.0 have been measured in Shenandoah poor, and granitic rocks are intermediate. National Park. Each of the three bedrock types underlies approximately one-third of SNP. Shenandoah National Park has 231 headwater streams in which ANC and pH decrease to various degrees, depending on the geology and topography. In general, Streams start as the steeper the slope, the more quickly acid Streamwater Streamwater seeps on a hillface rain reaches the stream with less chance of pH = 6.1 pH = 4.5 ANC = 150 More desirable environment being neutralized along ANC = 5 for fish and other aquatic biota the way. Therefore, a Poor environment for a small stream near the diverse population of fish Streamwater crest of a mountain, pH = 7.2 and other aquatic biota ANC = 250 on a steep slope, and Soil underlain by siliciclas- tic bedrock, is likely Basaltic Bedrock to have some of the Streamwater most acidic water in pH = 4.6 Siliciclastic Bedrock ANC = 15 SNP (fig. 2). Such streamwater does not support a diverse popu- lation of aquatic biota. Conversely, a large stream with a gentle slope and underlain by basaltic bed- Figure 2. Two stream systems with different characteristics that result in differences in water quality. rock will have near-neutral Whether or not the aquatic biota will be diversified is strongly controlled by the geology and topography. water and, consequently, a diverse population of aquatic biota (fig. 2). Front Royal Entrance Station Front Royal Washington, D.C. Shenandoah Dickey Ridge Visitor Center Waynesboro National Park CHESAPEAKE Richmond Mathews Arm BAY 78o15' VIRGINIA ATLANTIC OCEAN 38o45' Elkwallow Shenandoah National Park Facts Skyline Drive • Consists of 308 square miles (nearly Thornton Gap Entrance Station 200,000 acres) • Straddles the crest of the Blue Ridge Mountains Panorama • Stretches from Front Royal in the north to Rockfish Gap in the south, with Skyline Drive traversing the entire length Skyland • Touches eight counties (Albemarle, Augusta, Byrd Visitor Center Greene, Madison, Page, Rappahannock, 78o30' Rockingham, and Warren) 38o30' • Has 231 headwater streams Big Meadows • Contains three main types of bedrock Skyline Drive (basaltic, granitic, and siliciclastic) Lewis Mountain • Has land-surface elevations that range from about 600 to 4,051 feet Swift Run Gap Entrance Station 78o45' EXPLANATION MINIMUM ANC VALUES 38o15' Skyline Drive Less than or equal to 50 units (poor ability to neutralize acidity) Loft Mountain Greater than 50 units (better ability to neutralize acidity) Shenandoah National Park boundary Watershed boundary 0 5 10 MILES 0 5 10 KILOMETERS Rockfish Gap Entrance Station Figure 3. Predictions of Shenandoah National Park watersheds that are likely to have a minimum average acid-neutralizing capacity (ANC) less than or equal to 50 units (red) or greater than 50 units (blue) for 6 consecutive hours about once every 4 years. The watersheds shown in red have the greatest likelihood of losing native aquatic species because of extended periods of low ANC. Models and Predictions These results are of concern because Scientists studied streamwater data from five SNP streams and developed a they indicate a high probability for loss specific mathematical model for each of of native aquatic species in the park. the five watersheds based on mathemati- cal relations among ANC decreases in each stream and the geologic and topo- graphic characteristics of the watershed One-half of the SNP watersheds are For additional details about the (Rice and others, 2005).
Load more

Recommended publications
  • Big Meadows Area - Shenandoah National Park National Park Service U.S
    Big Meadows Area - Shenandoah National Park National Park Service U.S. Department of the Interior 11/2020 A map of the Big Meadows area in Shenandoah National Park, MP Red Gate 49 Fire Road Fishers Gap l i Overlook a Big Meadows R r T Picnic Grounds o s Amphitheater il e Rose River ra Falls (67’) T e s r o H Lodge s R w i o v e p d r o a l e o i L a M r T g Big Meadows i s r l ve l B i Blackrock - R a Campground d MP F S F n 0.4 mile 50 i t r g e o a l in r r y y k p S S o er s f Riv i se o w th R e e R ose Fi L F o R re or a e d s t Sto n Air Quality y Ro T a Monitoring r d Station a Dark Hollow il Falls Trail Lewis Falls P Dark Hollow (81’) Dark Hollow Falls Falls (70’) MP Parking No Pets M o Tanners Ridge 51 u Civilian Conservation n Overlook P Corps camp t Visitor Center a i P n Wayside ad THE MEADOW o R T r a i e Ra l ir Rapidan Road pid F an Parking F e ire g d i R Ro MP ad 52 s R r a e p n i n d a a T n l i a r T Road R a p i d a e n s r F o i r H e P ro re T l n i ng ra l g F o i UpperUpper Dark Dark Pr il Milam Gap M HollowHollow Falls Trail P Parking M ill North R o ad MP 53 Hiking Trail Paved Road 0 1 Kilometer Hiking Trail (Appalachian Trail) Skyline Drive Hiking Trail (Horses) Park Boundary 0 1 Mile Unpaved Road Stream Unpaved Road (Horses) P Parking Building Viewpoint Waterfall Emergency 1-800-732-0911 • Information 540-999-3500 • Online www.nps.gov/shen Dark Hollow Falls Hike Markers & Blazes 1.4-mile round trip 1.25-hours hiking time Trail markers are at trailheads and Moderate 440-foot elevation gain intersections.
    [Show full text]
  • Where Is Afton Mountain? Christopher M
    Worthy Field Locales THE GEOLOGY of VIRGINIA Mind the Gap! Where is Afton Mountain? Christopher M. Bailey, College of William & Mary Ask Virginians where the top of Afton y e Mountain is located, and they will ll likely tell you “it’s the place where a V s Interstate 64 crosses the Blue Ridge h n Mountains between Charlottesville and a i o ta Staunton”. The trouble with that de- d n n u scription is this: Interstate 64 crests the a o Blue Ridge Mountains at Rockfish Gap. n M e So where exactly is Afton Mountain? h Waynesboro S Look on the U.S. Geological Survey’s ge topographic map of the area and you’ll id not find an Afton Mountain. Afton is a R I-64 small town located on the slopes of the Blue Ridge about a mile to the east of Rockfish Gap. Interstate 64 cuts a long e gentle grade across the southern slope lu Rockfish of the Blue Ridge topping out at 1900 ft B Gap (580 m) above sea level at Rockfish Gap before descending westward into the 0 3 miles Shenandoah Valley. Rockfish Gap has 0 5 N long been an important nexus between kilometers the Piedmont and Shenandoah Valley, False color satellite image of the Blue Ridge Mountains, Shenandoah but as we shall see it is also a fascinat- Valley, and Rockfish Gap. ing geological locale. Rockfish Gap C. M. Bailey, W&M Geology Oblique aerial photo of Rockfish Gap and the crest of the Blue Ridge Mountains as viewed from the south-southeast.
    [Show full text]
  • Scenic Landforms of Virginia
    Vol. 34 August 1988 No. 3 SCENIC LANDFORMS OF VIRGINIA Harry Webb . Virginia has a wide variety of scenic landforms, such State Highway, SR - State Road, GWNF.R(T) - George as mountains, waterfalls, gorges, islands, water and Washington National Forest Road (Trail), JNFR(T) - wind gaps, caves, valleys, hills, and cliffs. These land- Jefferson National Forest Road (Trail), BRPMP - Blue forms, some with interesting names such as Hanging Ridge Parkway mile post, and SNPMP - Shenandoah Rock, Devils Backbone, Striped Rock, and Lovers Leap, National Park mile post. range in elevation from Mt. Rogers at 5729 feet to As- This listing is primarily of those landforms named on sateague and Tangier islands near sea level. Two nat- topographic maps. It is hoped that the reader will advise ural lakes occur in Virginia, Mountain Lake in Giles the Division of other noteworthy landforms in the st& County and Lake Drummond in the City of Chesapeake. that are not mentioned. For those features on private Gaps through the mountains were important routes for land always obtain the owner's permission before vis- early settlers and positions for military movements dur- iting. Some particularly interesting features are de- ing the Civil War. Today, many gaps are still important scribed in more detail below. locations of roads and highways. For this report, landforms are listed alphabetically Dismal Swamp (see Chesapeake, City of) by county or city. Features along county lines are de- The Dismal Swamp, located in southeastern Virginia, scribed in only one county with references in other ap- is about 10 to 11 miles wide and 15 miles long, and propriate counties.
    [Show full text]
  • Catoctin Formation
    Glimpses of the Past: THE GEOLOGY of VIRGINIA The Catoctin Formation — Virginia is for Lavas Alex Johnson and Chuck Bailey, Department of Geology, College of William & Mary Stony Man is a high peak in Virginia’s Blue Ridge Mountains that tops out at just over 1200 m (4,000’). Drive south from Thornton Gap along the Skyline Drive and you’ll see the impressive cliffs of Stony Man’s northwestern face. These are the cliffs that give the mountain its name, as the cliffs and slopes have a vague resemblance to a reclining man’s forehead, eye, nose, and beard. Climb to the top and you’ll see peculiar bluish-green rocks exposed on the summit that are ancient lava flows, part of a geologic unit known as the Catoctin Formation. From the presidential retreat at Camp David to Jefferson’s Monticello, from Harpers Ferry to Humpback Rocks, the Catoctin Formation underlies much of the Blue Ridge. This distinctive geologic unit tells us much about the long geologic history of the Blue Ridge and central Appalachians. Stony Man’s summit and northwestern slope, Shenandoah National Park, Virginia. Cliffs expose metabasaltic greenstone of the Neoproterozoic Catoctin Formation. (CMB photo). Geologic cross section of Stony Man summit area (modified from Badger, 1999). The Catoctin Formation was first named by Arthur Keith in 1894 and takes its name for exposures on Catoctin Mountain, a long ridge that stretches from Maryland into northern Virginia. The word Catoctin is rooted in the old Algonquin term Kittockton. The exact meaning of the term has become a point of contention; among historians the translation “speckled mountain” is preferred, however local tradition holds that that Catoctin means “place of many deer” (Kenny, 1984).
    [Show full text]
  • Shenandoah National Park Project Virginia
    SHENANDOAH NATIONAL PARK PROJECT VIRGINIA White Oak Canyon UNITED STATES SHENANDOAH NATIONAL PARK PROJECT DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary In the Blue Ridge Mountains of Virginia NATIONAL PARK SERVICE Arno B. Cammerer, Director national park in the Virginia section of the Blue Ridge Mountains was authorized by an act of Congress approv­ A ed May 22, 1926. The act specified that when title to 250,000 acres of a tract of land approved by the Secretary of the Interior should be vested in the United States, it would constitute a national park dedicated and set apart for the benefit and enjoyment of the people, and the Government would VIRGINIA STATE COMMISSION proceed with the installation of accommodations for visitors, ON the development of an adequate road and trail system, the CONSERVATION AND DEVELOPMENT stocking of fishing streams, and the inauguration of an educa­ William E. Carson, Chairman tional service to acquaint the public with the historical back­ ground and natural beauty of this famous region. Upon the passage of the act, the State of Virginia, through its Commission on Conservation and Development, im­ mediately began the work of acquiring the money to purchase SHENANDOAH NATIONAL PARK PROJECT the necessary land. This was a tremendous undertaking as the approved area was made up of thousands of parcels of privately VIRGINIA owned land. Funds were raised through State appropriations, contributions from citizens of Virginia, and from outside sources. The work moved forward with all possible expediency until the period of general depression set in, and it became increasingly difficult to obtain funds.
    [Show full text]
  • Shenandoah National Park Virginia
    A fact sheet from 2017 The Pew Charitable Trusts $191,000 is needed to repair one of the park’s two surviving Civilian Conservation Corps buildings, which date to the Great Depression. The Pew Charitable Trusts Shenandoah National Park Virginia Overview Over a million people enter Shenandoah National Park’s gates each year, most taking the Skyline Drive to vantage points along 105 miles of the Blue Ridge Mountains. The 200,000-acre park tracks the spine of the mountains in the northwestern corner of Virginia. From pullouts or granite peaks accessed by more than a dozen hiking trails, visitors have spectacular views of the state’s Piedmont region and Shenandoah Valley—particularly during peak fall foliage. Shenandoah is an early example of environmental planning and design in the National Park System. In the early 1900s, people living as far away as Washington built summer retreats here. When the park was established in 1935, more than 10,000 boys and young men in the Civilian Conservation Corps tore down most of these structures and nearly all homes built by early European settlers to create a more natural setting. They also carved trails—which now span over 500 miles—and built other park infrastructure. The park encompasses parts of eight counties and its restoration has allowed Congress to designate roughly 40 percent of it as wilderness areas. That wilderness draws scientists conducting ecological research ranging from bear behavior to the effects of acid rain, in addition to hikers. Unfortunately, Shenandoah faces a maintenance backlog of over $90 million, more than half of which is for road repairs.
    [Show full text]
  • The Louisa Railroad (1836-1850) Charles W
    University of Richmond UR Scholarship Repository Honors Theses Student Research 1937 The Louisa Railroad (1836-1850) Charles W. Turner Follow this and additional works at: https://scholarship.richmond.edu/honors-theses Part of the History Commons Recommended Citation Turner, Charles W., "The Louisa Railroad (1836-1850)" (1937). Honors Theses. 1051. https://scholarship.richmond.edu/honors-theses/1051 This Thesis is brought to you for free and open access by the Student Research at UR Scholarship Repository. It has been accepted for inclusion in Honors Theses by an authorized administrator of UR Scholarship Repository. For more information, please contact [email protected]. UNIVERSITYOF RIC HMONDLIB RARIES llllll~llll~~iililllllllm~llll~IIIIII _ . 3 3082 01028 3231 THE· 'LOUISA RAILROAD (1836-1850) History Thesis May 24 ,1937. Presented by Charles w. Turner. (In this paper, there will be found facts concerning the lives of many of the characters connected with the railroad.) BIBLIOGRAPHY Books 1. Freeman, D.S., R. E. Lee, Vol. II, III, IV, Charles Scribners Sons, NewYork, N. Y., l934-36. 2. Harris, Malcohn H., ~ History of Louisa County, Virg~n1a, The Dietz Presa, Ric~mond, V1rg1n1a, 1937. 3. Morton, R. L., Historx of V1r5lnia, Vol. III, Amertcan Historical Society, New York, N. Y. 1924. 4. Nelson, James P., Hlstor~ of the c. and o. Ra11 a~ Co., I.ew1e Printing Company, R1cnmond, -VirginTa, -r~ 7. -- Newspapers and Magazines 6. Reli6ious He~ald, ~eb. 13, 1873~ 7. Richmond Ingui-rer, 1835-50• 8. Stanard, W. G. ed., Virginia Historical Magazine, Vol. XXIX, Virginia Historical Society, Richmond, Virginia, 1921. · 9. Stanard, w.
    [Show full text]
  • Railroad Building in Virginia (1827 to 1860)
    Railroad Building in Virginia (1827 to 1860) Virginia History Series #10-08 © 2008 Major Railroads in Virginia (from 1827-1860) • Baltimore and Ohio (1827) – Winchester & Potomac (at Harpers Ferry) – Winchester & Strasburg • South Side or “Petersburg & -- North Western to Lynchburg RR” (1849-54) Parkersburg, WV • Richmond & Danville (1847-1856) • Manassas Gap (1850-54) • Petersburg & Roanoke (river in NC) • Orange & Alexandria (1848) (1833) -- Richmond & Petersburg (1838) • Virginia Central (1836) -- Blue Ridge (1858) • Norfolk and Petersburg (1853) • Virginia & Tennessee (1850s) • Seaboard & Roanoke (river in NC) or “Portsmouth and Weldon RR” (1835) • Richmond, Fredericksburg, and Potomac to Alexandria (1834) & Fredericksburg & Charlottesville RR Major RR Routes in Virginia by 1860 Wheeling●, Ohio River Parkersburg ● ● Grafton Maryland & York RR+ + ++++++/ + Norfolk Stn + Petersburg & + Norfolk RR + + + + Suffolk Stn + + Bristol ● + + + + Norfolk & + Roanoke RR Weldon ■ On March 8, 1827, the Commonwealth of Virginia joined Maryland in giving the Baltimore and Ohio Rail Road (B&O RR) the task of building a railroad from the port of Baltimore, MD West to a suitable point on the Ohio River. The railroad was intended to provide a faster route for Midwestern goods to reach the East Coast than the successful Erie Canal across upstate NY. Construction began on July 4th, 1828. It was decided to follow the Patapsco River to a point near where the railroad would cross the “fall line” and descend into the valley of the Monocacy and Potomac Rivers. Thomas Viaduct (on the B&O RR) spans the Patapsco River and Patapsco Valley between Relay and Elkridge, MD (1833-35) It was the largest bridge in the nation and today its still the world's oldest multiple arched stone railroad bridge Further extensions of the B&O RR soon opened to Frederick and Point of Rocks on the Potomac river.
    [Show full text]
  • Climate Summary, Shenandoah National Park
    National Park Service U.S. Department of the Interior Northeast Region Philadelphia, Pennsylvania Climate Summary, Shenandoah National Park Natural Resources Report NPS/NER/NRR—2007/017 ON THE COVER From top left to bottom right: Ice along Skyline Drive; courtesy of the National Park Service, Shenandoah National Park, Nature & Science (Environmental Factors - Weather) Archives; http://www.nps.gov/shen/naturescience/weather.htm. A couple pausing to take in a scenic view from Skyline Drive; courtesy of National Park Service, Shenandoah National Park, History & Culture Archives; http://www.nps.gov/shen/historyculture/skylinedrive.htm. Landslides after heavy rain storms; courtesy of the National Park Service, Shenandoah National Park, Nature & Science (Environmental Factors - Hydrological Activity) Archives; http://www.nps.gov/shen/naturescience/hydrologicactivity.htm. Climate Summary, Shenandoah National Park Natural Resources Report NPS/NER/NRR—2007/017 Stephen Gawtry and Jerry Stenger University of Virginia Climatology Office PO Box 400123 University of Virginia Charlottesville, VA 22904-4123 December 2007 U.S. Department of the Interior National Park Service Northeast Region Philadelphia, Pennsylvania The Northeast Region of the National Park Service (NPS) comprises national parks and related areas in 13 New England and Mid-Atlantic states. The diversity of parks and their resources are reflected in their designations as national parks, seashores, historic sites, recreation areas, military parks, monuments and memorials, and rivers and trails. Biological, physical, and social science research results, natural resource inventory and monitoring data, scientific literature reviews, bibliographies, and proceedings of technical workshops and conferences related to these park units are disseminated through the NPS/NER Technical Report (NRTR) and Natural Resources Report (NRR) series.
    [Show full text]
  • Addendum No. 2
    Addendum No. 2 Issue Date: 22 May 2017 To: Bidding Contractors - Plan Holders Project: Blue Ridge (Crozet) Tunnel Rehabilitation and Trail Project Nelson County Board of Supervisors The following items are being issued here for clarification, addition or deletion and have been incorporated into the Construction Documents and Project Manual, and shall be included as part of the bid documents. All Contractors shall acknowledge this Addendum No. 2 in the Bid Form. Failure of acknowledgment may result in rejection of your bid. All Bidders shall be responsible for seeing that their subcontractors are properly apprised of the contents of this addendum. BID DATE AND TIME: 1. The sign in sheet from the pre-bid meeting held on Friday May 12 th is included with Addenda 2. 2. At this time, the bid opening remains May 31 st at 2.00 PM. CLARIFICATIONS / CONTRACTOR QUESTIONS: 1. Q: The unit of measurement for the aggregate base material is in cubic yards. Can the units be revised to reflect the number of tons? A: Section 607.12 Unit Costs and Measures provides for the acceptable units for measurement. The quantity reflected in the bid form is based upon the area x thickness of the material. Please note that the volume is measured as “in-place and does not account for any volumetric loss due to compaction. The conversion from cubic yards to tons is based upon the unit weight of the material. For example, assuming a unit weight of 130 lbs/ft 3, which may be considered normal for VDOT 21B material, the conversion to tons would be 1 CY x (27 ft 3 / yd 3) x (130 lbs/ft 3) x (1 ton/2000 lbs).
    [Show full text]
  • Mm Wttmn, the Shenandoah Valley Became an Artery of Critical Impor­ Soil Forest in the South Section of the Park
    Shenandoah NATIONAL PARK VIRGINIA mm wttMN, The Shenandoah Valley became an artery of critical impor­ soil forest in the south section of the park. The characteristically tance during the War Between the States. General Jackson's dwarfed appearance of the deciduous trees overtopped by pine Shenandoah valley campaign is recognized as a superb example of military serves to distinguish the dry-soil forest from the moist-soil tactics. The mountain gaps within the park were strategically forest which predominates in the park. NATIONAL PARK important and were used frequently during these campaigns. Certain sections of the park support a variety of shrubs. The idea for a national park in the Southern Appalachian Notable among these are the azalea, the wild sweet crabapple, The Blue Ridge Mountains of Virginia are famed for their Mountains originated in the early 1920's. In succeeding years, and the hawthorn which bloom in May, followed in summer by scenic loveliness, romantic setting, and historical association. the State and people of Virginia, together with public-spirited the ninebark, Jersey-tea, and the sumac. During late May and In the heart of these lofty mountains is the Shenandoah Na­ conservationists from other parts of the United States, purchased June the mountain-laurel transforms whole mountainsides into tional Park. Its majestic tree-covered peaks reach elevations of 176,430 acres of Blue Ridge Mountain lands. This area was a mass of bloom. more than 4,000 feet above the sea. Much of the time these deeded to the Federal Government for administration and Trees with a profusion of conspicuous blossoms include development as a national park in 1935.
    [Show full text]
  • Shenandoah National Park U.S
    National Park Service Shenandoah National Park U.S. Department of the Interior Park Emergency Number (800) 732-0911 01/13 Big Meadows Road and Trail Map Park Information recording: (540) 999-3500 www.nps.gov/shen You’llYou’ll findfind thesethese trailtrail markersmarkers at aallll ttrailheadsrailheads aandnd inintersections.tersections. TThehe metametall bbandsands aarere stamstampedped witwithh didirectionalrectional andand mileagemileage information.information. d a o R e r i F r e v i R il Tra e s op o Lo R er iv R se o R Observation Point Dark Hollow Falls Trail – 1.4 miles round trip; very steep; 70' waterfall. Pets are not allowed. Story of the Forest Trail – 1.8-mile easy circuit that passes through forest and connects with paved walkway. From the Byrd Visitor Center front exit: turn right, follow sidewalk to trail entrance. At paved walkway turn left to return to visitor center, or to avoid pavement, retrace steps. Pets are not allowed. Lewis Falls Trail – 3.3-mile circuit from amphitheater to observation point, returning * via Appalachian Trail, or 2 miles round trip from Skyline Drive. 81’ waterfall. Moderate with steep, rocky areas; one stream crossing. Rose River Loop Trail – 4-mile circuit from Fishers Gap. Moderate, shady trail with stream, cascades, waterfall. Note: Round trip hikes proceed to a destination and return by the same route. Circuit hikes begin and end at the same point without retracing steps. * Horses are allowed only on yellow-blazed fire roads and trails. Leave No Trace Preservation through education: building awareness, appreciation, and most of all, respect for our public recreation places.
    [Show full text]